This invention relates to a process for the production of ammonia from a synthesis gas produced by partial oxidation without the presence of a catalyst.
The commercial synthesis of ammonia is usually achieved from a synthesis gas containing hydrogen and nitrogen, in a ratio preferably close or equal to the stoichiometric H.sub.2 :N.sub.2 ratio of 3:1 , and inert gases such as methane and argon which should be minimized as much as possible. The synthesis gas may be produced by catalytic steam reforming, such as the process described in U.S. Pat. No. 4,153,673, catalytic oxygen reforming, such as the process described in French Pat. No. 1,158,617 and an article entitled "Topsoe-SBA Autothermal Process" in Nitrogen 35-38 (May 17, 1962), or partial oxidation, such as the process described in U.S. Pat. No. 3,929,429. In partial oxidation, air has not been used in the reactor because it would result in a synthesis gas containing much more nitrogen than is required for ammonia synthesis. Either pure oxygen, or oxygen-enriched air have been used in these processes. In U.S. Pat. No. 2,795,559, however, a process is described in which air is used as the only source of free oxygen in the partial oxidation reactor. The excess nitrogen is removed in a cryogenic separation step before ammonia synthesis in order to obtain the proper H.sub.2 :N.sub.2 ratio of 3:1 to feed the synthesis loop.